Plasma Cholesterol-Lowering Effects of Soymilk and Okara Treated by Lactic Acid Fermentation in Rats

Abstract

We investigated the e#ect of lactic acid-fermented soymilk, in which a portion of soymilk was replaced with okara, on plasma and liver lipid concentrations in rats. Male Sprague-Dawley rats were fed a high-cholesterol diet (control diet) or test diet in which ,*῍ of the diets were replaced by soymilk, fermented soymilk or a fermented soymilk/okara mixture. Fermented soymilk/ okara was expected to be smoother in taste because finely powdered okara was used, instead of intact soybeans. Only rats fed a fermented soymilk/okara diet showed a significantly and continuously lower level of plasma total cholesterol. The hepatic triglyceride concentration in the rats fed the soymilk and fermented soymilk/okara diets showed significantly lower levels than rats fed the control diet. These results suggest that a mixture of fermented soymilk and okara has a significant advantage of the beneficial e#ects of okara, and shows greater plasma cholesterol-lowering and hepatic lipid-lowering e#ects than fermented soymilk alone. Therefore, fermented soymilk/ okara is available as a functional food for prevention of hyperlipidemia. In addition, okara, which has been discarded as industrial waste, could be e$ciently used as fermented soy food.

Effects of Lactobacillus Fermented Soymilk and Soy Yogurt on Hepatic Lipid Accumulation in Rats Fed a Cholesterol-Free Diet

“…However, the hepatic cholesterol content of the rats that ingested soy yogurt was not significantly suppressed as compared with the CO group (Table 4). In our previous studies, hepatic cholesterol contents fell in rats fed a high-cholesterol diet 16) and a cholesterol-free diet with ingestion of SY. 17) However, in the present experiment, the level of hepatic cholesterol in the rats fed soy yogurt showed only a tendency towards decrease (p < 0:01 vs. control).…”

“…DNA microarray analysis indicated that soy yogurt ingestion downregulated lipogenesis and cholesterol synthesis, and up-regulated -oxidation of fatty acid and cholesterol catabolism. Suppression by soy yogurt of hepatic lipids in rats fed a high-cholesterol diet 16) and a cholesterolfree diet 17) depended on the regulation of synthesis and degradation of lipids.…”

“…In spite of containing okara, soy yogurt had a smooth taste because finely powdered okara was used instead of commercial rough okara. We have investigated the effect of soy yogurt in decreasing plasma lipid in rats fed a high-cholesterol diet 16) and reducing hepatic lipid in rats fed a cholesterol-free diet. 17) Soy yogurt showed suppression of hepatic and plasma lipids in rats fed a high-cholesterol diet and a cholesterol-free diet.…”

Effects of Lactic Acid-Fermented Soymilk on Lipid Metabolism-Related Gene Expression in Rat Liver

“…We prepared soymilk fermented with lactic acid bacteria of vegetable origin in order to ingest it more easily. We have previously reported that fermented soymilk reduced the plasma and hepatic cholesterol concentrations in rats fed on a high-cholesterol diet 13) and that more than a 10% of soy protein in the diet was necessary to achieve a significant physiological effect on rats fed with a cholesterol-free diet by ingesting fermented soymilk. 14) Fermented soymilk prepared by using bifidobavterium breve YIT 4065 has been reported to improve the lipid metabolism.…”

Effect of Soy Yogurt (Lactic Acid-Fermented Okara in Soymilk) on Intestinal Polyamine Level in Rats

“…We examined the beneficial use of okara supplemented in lactic acid-fermented soymilk (soy yogurt). We already investigated the effects of soy yogurt on plasma and hepatic lipid profiles in rats (Kitawaki et al, 2007) and found that soy yogurt exhibits lipidmetabolism modification (Kitawaki et al, 2009).…”